The malfunctioning of protein kinases (PKs) is the hallmark of numerous diseases. A large share of the oncogenes and proto-oncogenes involved in human cancers encode for PKs. The enhanced activities of PKs are also implicated in many non-malignant diseases, such as benign prostate hyperplasia, familial adenomatosis, polyposis, neuro-fibromatosis, psoriasis, vascular smooth cell proliferation associated with atherosclerosis, pulmonary fibrosis, arthritis glomerulonephritis and post-surgical stenosis and restenosis.
PKs are also implicated in inflammatory conditions and in the multiplication of viruses and parasites. PKs may also play a major role in the pathogenesis and development of neurodegenerative disorders.
For a general reference to PKs malfunctioning or deregulation see, for instance, Current Opinion in Chemical Biology 1999, 3, 459-465 and Carcinogenesis 2008, 29, 1087-1091.
Originally identified as activated genes by proviral mutagenesis in a lymphoma mouse model, PIMs (PIM1, PIM2 and/or PIM-3 throughout this application) are protein-serine/threonine kinases. PIM kinases are poorly expressed in normal tissues, and overexpressed or even mutated in a discrete number of human cancers, including Lymphoma, Leukaemia, Prostate, Pancreas and Gastric cancers [Shah et al. Eur. J. Cancer, 44, 2144-51, (2008)].
PIM kinases are constitutively active and their activity supports in vitro and in vivo tumor cell growth and survival through modification of an increasing number of common as well as isoform-specific substrates including several cell cycle regulators and apoptosis mediators. PIM1 but not PIM2 seems also to mediate homing and migration of normal and malignant hematopoietic cells by regulating chemokine receptor surface expression [Brault et al. Haematologica 95 1004-1015 (2010)].
There is increasing evidence that PIM1 and PIM2 kinases may be involved in mediating the oncogenic effects of some acute myelogenous leukemias (AML)-associated oncogenes. In particular, the oncogenic role of FLT3-mutations (ITD and KD mut., present in 30% of AMLs) and/or translocations involving the MLL gene (occurring in 20% of AMLs), (Kumar, et al. (2005) J. Mol. Biol. 348, 183-193). PIM1 is more expressed in FLT3-ITD-transformed AML cells than in WT bone marrow cells. Data suggest that PIM1 as well as PIM2 inhibition may mediate FLT3ITD-dependent death of AML cells. Interestingly, cells transformed by FLT3 mutations that confer resistance to small-molecule tyrosine kinase inhibitors were still sensitive to knockdown of PIM2, or PIM-1 and PIM-2 by RNAi (Kim et al. (2005) Blood 105:1759-67).
Moreover, PIM2 has been reported being over-expressed and associated with progression of several malignancies that originate from the B-cell lineage such as chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL) or myeloma (Cohen et al. (2004) Leuk. Lymphoma 94:51; Huttmann et al (2006) Leukemia 20 1774).
Interestingly, PIM and AKT/PKB seem to play partly redundant roles in mediating growth and survival of hematopoietic cells most probably due to overlapping substrates like BAD, p21WAF1/CIP1, p27KIP1, or Cot/Tp1-2 [Choudhary et al., Mol Cell. 36 326-39 (2009)].
PIM kinases have been shown to control mTOR inhibition (rapamycin) resistant, proliferation and survival. Therefore, a combination of small molecule inhibitors targeting several survival kinases might be essential for a powerful cancer therapeutic platform [Amaravadi R., et al. J. Clin. Invest. 2005, 115 (10) 2618-24]. Oncogenic protein synthesis through eIF4E binding protein 1 (4E-BP1) seems to be mTOR-independent and controlled by PIM-2. This observations suggest that the oncogenic eIF4F translation-initiating complex could be blocked with small molecules PIM-2 inhibitors [Tamburini J. et al. Blood 2009, 114 (8), 1718-27 and Brault L. et al. Haematologica 2010, 95 (6) 1004-1015].
Pyrazolo-quinazoline derivatives possessing kinase inhibitory activity have been also disclosed in WO 04/104007, in the name of Pharmacia Italia S.P.A. Some specific compounds of the aforementioned WO 04/104007 are excluded from the present general formula.
Despite these developments, there is still need for effective agents for said diseases.